Chain and sprocket gearing.



PATENTED JULY. 19, 1904.

V J. M. DODGE. CHAIN AND SPROGKET GEARING.

APPLICATION FILED SBPT.-13' 1901.

' 2 SHEETS-SHEET 1.

no MODEL.

. Z joujjm/ w 760101074/ No. 765,565. PATENTED JULY 19, 1904.

J. M. DODGE. CHAIN AND SPROGKET GEARING.

. APPLICATION mum SEPT. 13. 1901.

- D0 MODEL. 2 SHEETS-SHEET 2.

UNITED STATES Patented July 19, 1904.

PATENT OFFICE. I

JAMES M. DODGE, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THE LINK BELTENGINEERING COMPANY, OF PHILADELPHIA, PENNSYL- VANIA, A CORPORATION OFPENNSYLVANIA.

CHAIN AND SPROCKET GEARING.

SPECIFICATION forming part of Letters Patent No. 765,565, dated July 19,1904.

Application filed September 13, 1901. Serial No. 75,298. (No model.)

To all whom it may concern.-

Be it known that I, J AMES M. DODGE, a citizen of the United States,residing in Philadelphia, Pennsylvania, have invented certainImprovements in Chain and Sprocket Gearing, of which the following is aspecification.

The object of my invention is to so construct a sprocket-wheel fordrive-chains that chains having different pitch may be applied to thesame sprocket-wheel, thereby dispensing with the usual practice ofaccurately fitting each chain-link to the wheel; and a further'object ofthe invention is to so construct the sprocketwheel that as the chainwears the slack will be automatically taken up by the chain shifting itsposition on the teeth of the sprocketwheel. I

In the accompanying drawings, Figure 1 is a View of a portion of areversible sprocketwheel, illustrating my invention and showing a newchain in position. Fig. 2 is a view similar to Fig. 1, showing a chainwith elongated pitch; and Fig. 3 is a view of a sprocketwheel shaped torun in one direction only.

Referring in the first instance to Fig. 1, A is a wheel having teeth a,with inclined sides a. Between the teeth a are platforms 7), on whichthe joints of the links of the chain rest, and between each platform andeach link are recesses 0 for the intervening joints of the chain, asclearly shown in Fig. 1. Each platform is substantially at a right angleto a radial line drawn from the center of the wheel, and, as shown inthe drawings, I prefer to make the surface of the platform on a circulararc.

D is the drive-chain, in the present instance of the Ewartdetachable-link type, having joints d and d, formed by a pin on one linkand a socket in an adjoining link.

When the chain is new, it is fitted to th sprocket-wheel, as indicatedin Fig. 1, and when the wheel is turned in the direction of the arrowthe chain will be driven by the side walls a of the teeth a of thesprocket-wheel bearing against the joints d of the 'chain,while thejoints 0? rest upon the platforms between the teeth. When in thisposition, a straight line drawn from the center of one joint d to theother joint d will pass through the center of the jointd, so that whenthe chain is seated on the wheel there is no sliding motion of the chainupon the tooth as the wheel is rotated. When the chain wears, the pitchwill be elongated and the slack of the chain will be automatically takenup by the joints 0Z riding up the inclined surfaces a of the teeth a,thus increasing the pitch diameter, so that after considerable wear thechain will assume the position shown in Fig. 2 of the drawings.

It will be seen that while the joints d bear upon the platforms betweenthe teeth the joints d will assume a position aconsiderable distancebeyond the line drawn from the center of one joint d to the other.

The chain can wear until the joints (Z d are extended so far that a linedrawn from the center of one joint d to another joint d will cut throughthe center of the joint 0Z, when the chain should be discarded.

In Fig. 31 have shown a wheel arranged with a platform adjacent to oneside of the tooth. This form of wheel is intended to drive only in onedirection, being a modification of the wheel shown in Fig. 1.

I claim as my invention- The combination of a sprocket-wheel havingteeth and platforms alternating with the teeth, each platform being onan arc of a circle taken from the center of the wheel, with adrive-chain consisting of a series of open links, the bar of one linkresting in the socket of an adjoining link, the sockets of the alternatelinks being in contact with the teeth of the wheel while the sockets ofthe other links rest upon the platforms, so that as the chain wears thepitch-line of the alternate links will move farther from the center ofthe wheel, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

. JAMES M. DODGE. Witnesses:

WILL A. BARR, Jos. H. KLEIN.

